For interior or exterior decoration of a surface, such as a building, a home or a vehicle, decorative polyvinyl chloride (PVC) based surface coverings are well known and widely used.
However, such “PVC” coverings have the drawback of being permeable to certain substances. In order to prevent or limit this phenomenon, while also preventing or limiting the penetration into the covering of dirt regardless of its nature, it was proposed to cover the outer surface of the upper and visible layer of the surface covering with a polyurethane type protective covering. However, this solution does not solve the problem of contaminants, present on the surface to be covered, from entering the covering, for example contaminants from a bituminous surface, or from the adhesive used to bond the covering to the surface. These contaminants migrate through the various layers of the surface covering, which leads to deterioration of mechanical performance characteristics and the aesthetic appearance of the covering.
In addition, for the manufacture of a PVC-based surface covering, and in particular a multilayer product, the manufacture of one or more layers of the covering involves the use of PVC recycled from old decorative surface coverings. Certain compounds, for example the pigments used in the decorative layer of these recycled coverings, can be found in the new covering using recycled PVC. In the case of pigments, they lead to deterioration of the aesthetic appearance and, generally speaking, a yellowing phenomenon of the covering.
In order to reduce or eliminate the yellowing phenomenon and to maintain the mechanical performance characteristics of a PVC-based covering, the use of a barrier layer was proposed. Generally speaking, it is a polyester-based or polyamide film or coating. Polyvinyl alcohol, well known for its barrier properties in packaging films is not used for a PVC layer owing to its low adherence to PVC, and particularly for a PVC layer including a significant amount of mineral fillers.
Classically, the doubling of a barrier film or the coating of a barrier composition is performed on at least one face of the surface covering, generally between the support layer and the wear layer, possibly between the support layer and the decorative layer of the decorative covering.
If a coating step does not pose specific problems, the use of film measuring 10 μm to 20 μm thick has the drawback of requiring a doubling step, which becomes particularly critical during the continuous manufacture of a surface covering that is 4 meters or 5 meters wide for example, since such barrier films are generally available only in widths of 2 meters or 3.5 meters.
In addition, the use of a polyester-based or polyamide barrier layer renders the recycling of the PVC-based coverings, which encase them, very difficult or even impossible owing to the need for special treatment that is not compatible or hardly compatible with the majority of the recycling processes involving PVC surface coverings.